Field of the Invention
The present invention relates to a vehicle power control technique for reliably notifying a driver of a state of a power controlling state while giving an optimal driving force to a vehicle and for reducing a sense of discomfort resulting from the power control.
Description of the Related Art
A vehicle equipped with a traction control system (TCS) as an apparatus for increasing vehicle running stability is well known. The vehicle TCS is a technique for preventing driving wheels of the vehicle from spinning (slipping) by appropriately controlling a driving force during acceleration of the vehicle in a predetermined power control driving state.
In the vehicle, the driving force produced by an engine is finally transmitted to a road surface through tires of driving wheels. If gripping forces with which the tires grip a road surface are exceeded, the tires slip, making it difficult to transmit the driving force to the road surface.
The vehicle TCS is an apparatus which performs control to instantly reduce the driving force and thereby prevents the driving wheels from spinning when an excessive driving force larger than the gripping forces of the tires are applied to the driving wheels, causing the tires to slip during acceleration.
When a spin condition of the driving wheels is detected by various sensors, the vehicle TCS holds down engine power by controlling engine ignition timing or a throttle valve opening, and thereby recovers the gripping forces of tires gripping the road surface.
In the traction control system (TCS) of the vehicle, a technique for notifying a driver of traction control actuation, indicating that a traction control function is in actuated state generally notifies the driver by illuminating a lamp on an instrument panel as described in Patent Document 1 (Japanese Patent Laid-Open No. 2013-205395). However, in a driving state of a motorcycle, it is difficult for the driver, who drives staring ahead attentively, to check an illuminating state of the lamp, and the driver will not notice that the traction control function is in actuated state and may misunderstand that “acceleration has dropped unexpectedly” due to a drop in engine power.
Also, with the vehicle TCS, an amount of reduction in the driving force during traction control actuation is set beforehand, and cannot be changed freely. Consequently, when the driver tries to turn a corner by intentionally causing rear wheels to slip, the traction control actuation may make it difficult to do cornering or circular driving at will.
Furthermore, a cornering technique whereby the driver intentionally changes a direction of the vehicle by causing the rear wheels to slide (slip) during corner turning has been adopted in motor sports. If traction control is actuated during the corner turning, suppressing rear wheel spin, it becomes difficult for the driver to perform sliding control intentionally.